Intellisense is not showing TargetControlID in calendar control

I added AjaxControlToolKit through NuGet to my Visual Studio 2010, added a reference in my .aspx page. In the calendar c开发者_如何学Control, intellisense is not showing TargetControlID attribute. Can you help me in this. thanks !

Add a reference in your project to System.Web.Extensions.

I just ran into this in Visual Studio 2010, with both the 2006 and the Nov 2011 AjaxControlToolKit releases. Following normal rules I added a reference to AjaxControlToolKit, added the appropriate using statement, and there was no .TargetControlID field. When I got frustrated and put the property in (since all posts I found on Google said it worked for them!) and hit compile I got a complaint that I was missing a reference to System.Web.Extensions. Added it and up came all my "missing" attributes.